I'd be slightly concerned that you don't realise that a dm^3 is the SI unit for litres... (well, at least they're equal)
Titration calculation help!!!
- Thread starter icysniper
- Start date
I'd be slightly concerned that you don't realise that a dm^3 is the SI unit for litres... (well, at least they're equal)
Thanks. So M = mol/L = mol/dm3
M=mol/L therefore mol= M*L
=0.4*(20/1000)=0.008 moles or 8mmol for a and b
c) is M=mol/L
0.008/(25/1000)=0.32 M as the concentration of the nitric acid solution
I'll go with that too.
heres another then:
25cm³ of sodium carbonate reacted with 20cm³ of 0.2mol/dm³ of nitric acid
Na2CO3 + 2NaNO3 = 2NaNO3 + CO2 + H20
a) Calculate the number of moles of nitric acid in 20cm³.
b) Calculate the number of moles of sodium carbonate in 25cm³.
c) Calculate the concentration of sodium carbonate in mol/dm³
25cm³ of sodium carbonate reacted with 20cm³ of 0.2mol/dm³ of nitric acid
Na2CO3 + 2NaNO3 = 2NaNO3 + CO2 + H20
a) Calculate the number of moles of nitric acid in 20cm³.
b) Calculate the number of moles of sodium carbonate in 25cm³.
c) Calculate the concentration of sodium carbonate in mol/dm³
Last edited:
okay, my answer for a) is 0.63 moles of nitric acid
20/63
x2
= 0.63
since its 1:2, there must be half the moles for sodium carbonate
b) 0.63/2= 0.315
then for c) i did:
0.2/1000
x20
=0.004
1:2
so half 0.004 to get 0.002
0.002/25
x1000
= 0.08mol/dm³, is this correct???? :S
20/63
x2
= 0.63
since its 1:2, there must be half the moles for sodium carbonate
b) 0.63/2= 0.315
then for c) i did:
0.2/1000
x20
=0.004
1:2
so half 0.004 to get 0.002
0.002/25
x1000
= 0.08mol/dm³, is this correct???? :S
Just been afk, looks like you've got the hang of it whilst I've been away.
if you think this is intersting then wait until A Level where you should start doing electron orbits and then types of bonding and doing reaction equations showing electron changes
if you think this is intersting then wait until A Level where you should start doing electron orbits and then types of bonding and doing reaction equations showing electron changes
Soldato
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1:1 ratio of reactant molecules.
0.4mol/dm^3 = 0.0004mol/cm^3
20cm^3 x 0.0004mol/cm^3 = 0.008 moles
0.008 moles / 25cm^3 = 0.00032mol/cm^3
0.00032mol/cm^3 = 0.32mol/dm^3
You can skip the division and multiplication by 1000 entirely, but it can get confusing in the units, so make sure you know what you're doing
As for this:
Na2CO3 + 2HNO3
You have two moles of nitric acid to every one of sodium carbonate, so the ratio is 1:2.
a) 20cm^3 / 1000 = 0.02dm^3
0.02dm^3 * 0.2mol/dm^3 = 0.004 moles
b) 1:2 means there must be double the number of moles of nitric acid as sodium carbonate. If 20cm^3 of acid reacted exactly with 25cm^3 of the carbonate, you can simply halve the 0.004 moles. 0.002 moles.
c) 0.002 moles per 25cm^3
25cm^3 * 40 = 1000cm^3 = 1dm^3
0.002 * 40 = 0.08 = 0.08mol/dm^3
0.004mol
0.002mol
0.08mol/dm^3
0.4mol/dm^3 = 0.0004mol/cm^3
20cm^3 x 0.0004mol/cm^3 = 0.008 moles
0.008 moles / 25cm^3 = 0.00032mol/cm^3
0.00032mol/cm^3 = 0.32mol/dm^3
You can skip the division and multiplication by 1000 entirely, but it can get confusing in the units, so make sure you know what you're doing
As for this:
Na2CO3 + 2HNO3
You have two moles of nitric acid to every one of sodium carbonate, so the ratio is 1:2.
a) 20cm^3 / 1000 = 0.02dm^3
0.02dm^3 * 0.2mol/dm^3 = 0.004 moles
b) 1:2 means there must be double the number of moles of nitric acid as sodium carbonate. If 20cm^3 of acid reacted exactly with 25cm^3 of the carbonate, you can simply halve the 0.004 moles. 0.002 moles.
c) 0.002 moles per 25cm^3
25cm^3 * 40 = 1000cm^3 = 1dm^3
0.002 * 40 = 0.08 = 0.08mol/dm^3
0.004mol
0.002mol
0.08mol/dm^3